Introduction
Analyzing data often requires comparing rows, calculating rankings, finding running totals, or computing moving averages without changing the number of rows returned. Traditionally, these tasks required complex self-joins or nested subqueries, making SQL queries harder to write and maintain.
ClickHouse® Window Functions simplify these analytical operations by allowing calculations across a group of related rows while preserving every row in the result set. This enables cleaner SQL, better readability, and more powerful analytics.
In this guide, you'll learn what window functions are, how the OVER() clause works, and how to use the most common window functions in ClickHouse® with practical examples.
What Are Window Functions?
